<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .box{
            padding: 20px;
            border: 3px solid #000;
        }
    </style>
</head>
<body>
    <div id="id">
        <div class="box">
            <h3>小黑自动售货机</h3>
            <button @click="buy(5)">可乐5元</button>
            <button @click="buy(10)">咖啡10元</button>
            <button @click="buy(20)">草莓20元</button>
        </div>
        <p>银行卡余额：{{ money }}元</p>
    </div>
    <script src="../vue.js"></script>
    <script>
        const app = new Vue({
            el: '#id',
            data:{
                money: 100,
            },
            methods:{
                buy(price){
                    this.money -= price
                }
            }
        })
    </script>
</body>
</html>